This invention relates to an anchoring arrangement for safety belt buckles in vehicles, especially for safety belts encircling vertically adjustable seats of a motor vehicle. The vertical position adjuster for the seat is of the type which includes a clamping lever which is pivotably connected to the supporting frame for the vehicle seat, and a supporting beam secured to the vehicle body and having a clamping arm engaging the clamping lever in such a manner that during the vertical position adjustment of the seat the lever arm slides on the clamping arm and in the case of a collision the lever automatically becomes arrested thereon.
In conventional anchoring arrangements for adjusters of the above-described type the clamping lever is made in the form of an angular lever and pivotably supported on the frame of the vehicle seat. The seat frame is supported for longitudinal movement on two pairs of guiding rails and can be inclined at different angles relative to the floor of the vehicle. The belt buckle is pivotably supported for a limited angular movement on one end of the angular clamping lever whereas the other end of the clamping lever is shaped into a fork-like member which overlaps in the fashion of a guiding socket a supporting rail of which is pivotably attached to the body of the vehicle and which is provided on its lower side with a locking rack covered with a lining. The rack cooperates with a locking tooth provided at the free end of the fork-like portion of the clamping lever. This locking tooth is preferably in the form of a bolt which is rigidly connected to the fork-like guiding receptacle. The aforementioned arrangement of the two pairs of guiding rails which support the seat frame makes it possible that during a longitudinal adjustment of the seat, the seat frame is slightly angularly displaced and thus lifted or lowered. The belt buckle can take part in this angular movement of the seat frame since the clamping lever connected to the frame is longitudinally displaceable on the supporting rail, the latter being pivotable about a fixed pivot point on the vehicle body thus permitting a vertical displacement of the clamping lever. Accordingly the buckle on the safety belt maintains its fixed position relative to the seat irrespective of its adjustment. In the event of a collision the pulling force acting against the belt buckle turns the clamping lever in such a manner that the bolt acting as the arresting tooth penetrates the lining which is preferably made of a pliable plastic and engages the arresting teeth of the rack on the supporting rail. As a result, the pulling force from the belt buckle is transmitted via the clamping lever and the supporting rail into the vehicle body. In case of a collision the safety belt with its bucke performs, however, a forward movement because of the pivotal movement which is necessary for engaging the locking tooth of the clamping lever, and consequently the loop size of the safety belt increases. In addition during a collision the supporting rail swings upwardly until the line of action of the pulling force is aligned with the pivot point of the supporting rail on the vehicle body. As a consequence the loop of the safety belt is additionally increased so that the danger of injury to the user of the vehicle is also increased.